Hi!
I'm collecting parts for a mid engined BEC build. Need some input/advise to move forward.

I'm not too keen on an electric reverse and adding a reverse gearbox between the engine (turboed Hayabusa) and a rwd car diff puts the engine way to far forward. I'm nursing the idea of using an Audi transmission (A4?). The idea is to use a clutch center and make an adaptor for a "cardan joint" (wrong word?) and connect it to the outgoing shaft on the engine also using an adaptor (available "on the market" and a short prop shaft in between I'll use a support bearing for the "clutch center adaptor" mounted to the gearbox casing (using the interface for mounting onto the car engine.

Has this been done before?

Ideas and thoughts?

Seems massively complex and inefficient, not mention heavy way of doing things. Why not just turn the engine round, chain drive a powertec reversing differential.this will be cheaper, lighter, hugely more efficient and maintain the engine in it's usual orientation. It's tried tested and we use it in the Sabre race cars we build and it's just about bomb proof
Regards
Andy

Either what Andy B said, like he said tried and tested, or perhaps use an Elite diff with built in reverse. More expensive option mind you....

I've got a quaife powertec qba7r in mine and it's the business fair play, not cheap though.

Andy, if your reading this, sometimes my diff though will lock between forward and reverse, the selector is all the way over until it's touching the Ali mount but the diff will only go forward or backward 3/4 of a turn then it locks. Have you had any with this problem?

When I pop it in forward then, it works and won't lock for maybe a month or more?!?!

It's still the business though

Edit sorry for the thread hijack

[Edited on 14/3/12 by Stott]

quote:

---

Originally posted by Siduna
I'm not too keen on an electric reverse

---

quote:

---

I'm not too keen on an electric reverse

---

I started out with the intention of using chain drive (a Celica torsen diff to sort the cornering issues).

Then I got all these comments that a chain wouldn't take the load enough to be reliable. I'm looking at approx 300hp and roughly 600kg.

Thank's for the advise ... but I have to admit I feel a bit like a donkey between two haystacks.

What life expectancy can I expect with the power and weight according the above?

We use a chain drive with electric reverse using the standard Toyota MR2 Mk1 starter on the Furore F1. Works a treat as long as you don't want to reverse up a 1 in 7 or something like that & both cheaper & lighter than the gearbox alternatives. The chain should take it no problem, they run drag bikes on the same size chain you can use IIRC it's 530 or 626. We're running the ZZR1400 engine with wide rear tyres & mid engine, ok it's a bit less powerful & a bit lighter than what you're suggesting, but the first thing to break will always be the adhesion of the tyres to the road even on a hot day on slicks. All IMHO of course!

Using a bike engine to drive a car box is quite frankly a bonkers way around electric reverse (unless I've read it wrong?). It's akin to choosing to enter an F1 race with a mondeo because you don't like wearing helmets.

Elec reverse is tried and tested and pretty easy to set up. Will weigh what - 20kg at most?

[Edited on 14/3/12 by coyoteboy]

Yup as above, i think its defeating the object of bike engine if you then want to use a car box. Use an electric starter on a sprocket on the rear axle. Very cheap and reliable solution.

Thanks for your input guys!

The reason for not using a chain drive is because the risk of short life time on a chain drive. As for "dragbike chains", they are non O-ring type (referring to EK chains for dragrace applications) and according to their technical people that limits their life time. That's my experience after >20 Rosing motorcycles as well.

According to the general agent for EK chains breakages are an issue in Radical racing.

A bit surprised to learn from you guys that chain drive is bomb proof. I'm not questioning you! Kinda strange to get such opposite advise though.

What life expectancy do you have for a chain drive in aggresive driving?

I've never owned any of my demonstrators long enough to see any significant wear!!

1,000 miles of aggressive use chain needed retensioning a couple of times (after initial stretch/bed in when adjustment is significant), but couldn't discern any wear on either chain or sprockets - being realistic how many miles a year are you likely to do, many kitcars don't do more than 1500 a year,some of which will be gentle use, motorway/dual carriageway etc. so even 3,000 mile useage (which I think would be very extreme) would give a couple of years life probably.

TBH, if this is for road use, unless you have a death wish,or are fed upwith owning a driving licence then you're rarely going to see full throttle. With 190bhp & 560kg, I find you have to seriously rein yourself in b4 some insanely silly speeds come up! Was out in the lanes with it last w/e & I spent more time on trailing throttle than on the power!

quote:

---

Originally posted by russbost
I've never owned any of my demonstrators long enough to see any significant wear!!

1,000 miles of aggressive use chain needed retensioning a couple of times (after initial stretch/bed in when adjustment is significant), but couldn't discern any wear on either chain or sprockets - being realistic how many miles a year are you likely to do, many kitcars don't do more than 1500 a year,some of which will be gentle use, motorway/dual carriageway etc. so even 3,000 mile useage (which I think would be very extreme) would give a couple of years life probably.

TBH, if this is for road use, unless you have a death wish,or are fed upwith owning a driving licence then you're rarely going to see full throttle. With 190bhp & 560kg, I find you have to seriously rein yourself in b4 some insanely silly speeds come up! Was out in the lanes with it last w/e & I spent more time on trailing throttle than on the power!

---

quote:

---

Originally posted by russbost
I've never owned any of my demonstrators long enough to see any significant wear!!

1,000 miles of aggressive use chain needed retensioning a couple of times (after initial stretch/bed in when adjustment is significant), but couldn't discern any wear on either chain or sprockets - being realistic how many miles a year are you likely to do, many kitcars don't do more than 1500 a year,some of which will be gentle use, motorway/dual carriageway etc. so even 3,000 mile useage (which I think would be very extreme) would give a couple of years life probably.

TBH, if this is for road use, unless you have a death wish,or are fed upwith owning a driving licence then you're rarely going to see full throttle. With 190bhp & 560kg, I find you have to seriously rein yourself in b4 some insanely silly speeds come up! Was out in the lanes with it last w/e & I spent more time on trailing throttle than on the power!

---

I typically spend about 3000 miles on the bike a year so reaching 2000 in the car isn't totally impossible. Big country, few people and nice roads where I'm at.

So you guys think I should revitalise the plans for using the torsen diff and a chain drive?

Oh, if the guy responsible for the spell check in iPhones steps out in front of you ... don' waste your brake pads...

I'm using the standard size chain for the ZZR1400 which IIRC is 530, there is one slightly beefier than this which I think may be 626?(It's definitely 6xx), but there's not a lot of difference & it'snot so readily available. I just use an "O" ring chain from Triple S, mainly because I can get it from a wholesaler, I'm led to believe DID "X" ring is about the best.

Most of us in the RGB race series use DID ZVM2 or ZVMX 530 chains. As Russ said, after initial use these require minimal adjustment and I'm not aware that we've had any breakages in RGB (we're running standard engines up to about 180bhp and Yoko 48R tyres). I'm aware some of the bikesports guys have had breakages but don't know what chains they use, they are however often running tuned big bore Busas and slicks.

If this is a road car and the chain and sprocket alignment is perfect I don't see a big issue. Again agreeing with Russ use of sustained full throttle on the road in one of these cars is generally inconsistent with either a long life or a valid driving licence!

Chain life, in my limited experience with them, depends rather heavily on the accuracy of the parts that it's fitted to. If your diff hanging and tensioning is wrong, even slightly, it'll die in a matter of miles. If you have a way of keeping that lot nicely aligned and tensioned correctly it should be fairly bomb proof.

In Bikesports i've only ever seen a radical break a chain, and that the guy said that the chain had been on the car 8 odd years so if your worried about it, replace it but remember these radicals are running 200+ bhp and running slicks and they go when they are redlining on the start line dumping the clutch. Something that doesnt regularly happen on the road or even trackdays.

What typical ratio between sprockets are you using and what tire diameter? Given the fact that I'm building a heavier car but with a more powerful engine I guess the same ratio, after compensating for difference i tire diameter, could be a good starting point. I'll be running 245/15x45.

Ordered 16-front 48-rear sprockets today. 225/45x15 tires at the rear.

Feedback?


Starter driven reverse: -What not to do?

Decided to go with twin 530 chains and electric reverse ... parts in manufacturing.

I'll be using drive shafts, spindles and hubs from a Mazda Miata. Aiming at 0,02-0,03 degrees camber gain per mm travel in the fron suspension and a RC height at approx 30mm. Any comments?

The whole point of a BEC, CEC or any performance kitcar is weight.

Keep it minimal and locost, if a chain fails it will be relatively cheap and easy to change.

Not sure how much an A4 transmission weighs. Over my 3 years of building ive used the phrase KISS.

Keep It Simple Simon

As you can see above the idea with a A4 transmission is scrapped. The twin chains will add weight, I agree. But so does a complete diff house when using a prop "solution"...
Should it turn out the twin chains increases the weight beyound driveability it can always scrap one a go single chain drive.

A lot of excercise and proper food in enough portions also reduces weight

Why do you feel the need for twin chains?
As mentioned by others already, a properly aligned high quality chain is a proven solution.

I'm wondering if the dual chains may actually provide less service life due to the different wear rates and alignment issues.

Please keep us posted on your results.

Thanks
Chet

The reason I decided to use twin chains is based on recommendations from the agent but also from the technical dept at the chain manufacturer. It's one of the major players in high performance chains so I feel pretty confident in their statement. It's always possible to go back to single chain should it not work.

While you guys in the UK have full confidence in a single chain, people in other countries have not .... got me a bit puzzled to say the least ... better chains or car builders in the UK.

I finally reached out to one of the main chain manufacturers and got the advice from their technical manager... never thought I'd get a reply at all.

What I did then was to buy a "heavy duty" countershaft from APE Racing in the US. Currently I'm having adapters made, wire cutting the splines in the adapter shaft-sprocket, and the splines in the sprockets. The inner most sprocket will be closer to the engine housing than original (don't remember the exact dimension) and the outer with a c-c of roughly 27mm (chain clearance) on the outside. The result is that I'll extend the "bending arm" giving the bending momentum on the countershaft only by a couple of mm. The stronger shaft should, with margin, be strong enough to deal with the extended bending load. Having the splines made with wire cutting allows for extreme tolerances, which I think is key to get this working.

I'll keep you posted on progress! Will take some time before it's tested on the road though since the car isn't built yet ... hopefully I can get you guys to push me to finish it (if you're curious enough on the twin chain setup)?
From what I've heard the concept I'm building isn't that common (at least in Sweden) so there's not much bolt-on for me. I'm looking at building something like a "Dytona DP Corvettish" two seater with a middy Hayabusa with a rotating muffler (turbo). So I guess I'll get a chanse to practise carbon/glass fibre molding...

Current status is that I've done simulations on suspension geometry, bought spindles, hubs and drive shafts from a Mazda Miata. Next step is to make a "mock up" of the seats, pedals and stearing to be able to determine the space required to fit myself and a passanger. So you'll have to wait a bit for a test report of twin chain drive ... at least xx months..

By the way, I'll be using a Torsendiff from a Toyota Celica GT4 (-91). Anyone's got any experience from such a thing?

[Edited on 9/8/12 by Siduna]

[Edited on 9/8/12 by Siduna]

Thanks for the info.

It's always interesting to me to see how and why someone take a specific approach to resolve a design issue.
I've been involved with both front and rear engined Hayabusa powered cars here in the USA for about 10 years and I'm still learning from others.

Hopefully the HD shaft will handle the increased load without a problem.

One suggestion -You may want to consider designing the car to have enough physical space for a future turbo but just use a standard Hayabusa engine initially.
I'ts been my experience that a 190 HP Hayabusa in a lightweight car will provide more performance than you will believe. A standard engine will also greatly simplify your build and get you on the track / road much sooner.

Chet
Hayabusa powered J15
1000 lbs
0-60 mph in 3.1

Thanks for your input!
Since I'm still at the start of my project and whether or not I'll fit a turbo onto the engine many moons will pass before it will influence my project time wise. Either way I'll make sure there's space enought to fit turbo and intercooler.